Solution :
Here, we need to perform JOIN operation of the students and registration.
Use NATURAL JOIN operator 
and so no need to specify Join condition.
Also we need to selection operator tp select only those course whose major in "philosophy".
Finally we projection operator π to project only distinct students name who took at least three courses.
![$\pi [\sigma_{\text{student's nam}e} [ \sigma(\text{three courses}) \Join \text{"Philosophy"}]]$](https://tex.z-dn.net/?f=%24%5Cpi%20%5B%5Csigma_%7B%5Ctext%7Bstudent%27s%20nam%7De%7D%20%5B%20%5Csigma%28%5Ctext%7Bthree%20courses%7D%29%20%5CJoin%20%5Ctext%7B%22Philosophy%22%7D%5D%5D%24)
I would have to say it would be A. log file.
Answer:
I would say if it is a multiple choice
Explanation:
q3 or q5 would be the best ones to pick from in my eyes.
Complete Question:
The main disadvantage of using this device is its negative impact on network performance, resulting from the fact that any incoming signal on any of its ports is re-created and sent out on any connected ports.
Group of answer choices
a. Router
b. Switch
c. Bridge
d. Hub
Answer:
d. Hub.
Explanation:
A hub can be defined as a layer one (physical) device used for connecting various network devices such as switches and routers in a local area network (LAN). It comprises of many ports which are used for connecting segments of a local area network (LAN). Hubs are generally considered to be unintelligent because when frames are received at a port, it is then copied to every other connected port on the network.
<em>Hence, the main disadvantage of using a hub is its negative impact on network performance, resulting from the fact that any incoming signal on any of its ports is re-created and sent out on any connected ports.</em>
Answer:
Don't do it. People will sue you even though it was put on the internet.
Explanation:
